The present invention relates to antenna equipment which is provided with a main reflector, a subreflector and a primary radiator, and more particularly to a multi-reflector antenna in which the aperture distribution is rotationally symmetric.
A conventional parabolic antenna or the like of an axially symmetric structure has a substantially axially symmetric aperture distribution on one hand but on the other hand suffers lowered gain and degraded side lobe characteristics resulting from blocking in the aperture plane of the primary radiator or the like. In case of employing an offset structure with a view to avoiding the blocking, an asymmetric aperture distribution due to the asymmetric structure will generally reduce the gain and deteriorate the side lobe characteristics and cross polarization characteristic.
However, the above defects of the prior art have not yet been eliminated.